A cured product formed by curing a curable composition has such merits that (i) by an imprinting method, an injection molding method or the like, it is possible to form a cured product of a variety of shapes from a curable composition in a short time, that (ii) it is less likely to break as compared with glass and that (iii) it is light in weight as compared with glass, and thus, it has attracted attention as a material for optical members in place of glass.
As a camera lens to be mounted on e.g. a mobile phone, which is required to be downsized, a wafer level lens has been used. A wafer level lens is required to have a high refractive index, a low Abbe number, high transparency and high heat resistance. Accordingly, a curable composition for forming such a wafer level lens is required to provide a cured product having a high refractive index, a low Abbe number, high transparency and high heat resistance.
As a curable composition from which a cured product having a high refractive index and high transparency is obtained, for example, the following (1) has been proposed.
(1) A curable composition containing a monomer having a fluorene skeleton and a monomer having a biphenyl skeleton (Patent Documents 1 and 2).
As a curable composition from which a cured product having a high refractive index and a low Abbe number is obtained, for example, the following (2) to (4) have been proposed.
(2) A curable composition containing a monomer having a fluorene skeleton, a monomer having no fluorene skeleton and a polymerization initiator (Patent Document 3).
(3) A curable composition containing a monomer having a bisphenyl sulfide skeleton or the like and a monomer having a fluorene skeleton (Patent Document 4).
(4) A curable composition containing a monomer having a carbazole skeleton and a monomer having a fluorene skeleton (Patent Documents 5).